1. Field of the Invention
The present invention relates to a camera which selectively performs several different combinations of the operations of photometry, distance measurement, display, focus adjustment, and exposure, according to the method in which a shutter release button is operated.
2. Description of the Related Art
A camera which executes the operation of preparing for photography when a shutter release button thereof is depressed partially as far as a first stroke position thereof and which exposes a film frame to actually perform photography when the shutter release button is depressed fully as far as a second stroke position thereof is per se known.
The operations which may be performed as preparation for photography include but are not limited to: photometry, measuring the photographic distance or focus adjustment detection operation, display actuation, and the like. The operation of photometry typically includes measuring the brightness level of the object to be photographed, calculating an exposure value based upon the brightness level of the object to be photographed and upon the sensitivity of the film which is currently loaded in the camera, and determining upon the most suitable combination of iris opening (aperture) and shutter speed based upon the calculated exposure value. The operation of measuring the photographic distance consists of the operation of detecting the photographic distance to the object to be photographed, while the operation of focus adjustment detection consists of detecting the focus adjustment state of the photographic lens. And the operation of display actuation consists of the actuation of an external display device or of a display device provided within the viewfinder of the camera, so as to display to the camera user the values of iris opening and/or shutter speed and the like which have been determined based upon the operation of photometry.
Further, a camera is per se known which also performs the operation of focus adjustment of the photographic lens during the above described first stage of preparation for photography, i.e. while the shutter release button is being depressed to its first stroke position, in order to shorten the shutter release time lag from the time point at which the shutter release button is first depressed all the way to its second stroke position to the time at which the action of exposure of the film frame actually starts. This operation of focus adjustment of the photographic lens consists of driving the photographic lens axially to an appropriate position for providing proper focusing, according to the photographic distance which is determined as a result of the photographic distance measurement operation or according to the defocusing amount which is determined as a result of the operation of focus adjustment detection.
With these types of prior art camera, when the shutter release button is depressed by the camera user quickly in one stroke all the way down to its second stroke position, i.e. through the first stroke position thereof without substantially pausing there, then the operation of exposing the film is only performed after all of the photographic preparation operations of photometry, measuring the photographic distance or focus adjustment detection operation, display actuation, focus adjustment, and the like have been completed.